Development of composite multi-layered PZT thin films for microactuator

Abstract

It is necessary to develop high performance microactuator in order to achieve it operating at very low applied voltage. This paper describes the development of composite multi-layered PZT thin films for microactuator. The piezoelectric properties for 8 kinds of composite multi-layered PZT thin films are fabricated and studied. The ferroelectric polarization - electric (P-E) hysteresis loops of the films is also measured and discussed. According to the results of P-E hysteriesis loops, for these different composite films, most optimum composite form - sol-gel + sputter composite double-layered PZT thin films, which combined with conventional RF sputtering and sol-gel processing methods, exhibit excellent remnant polarization and coercive fields of 14.87 uC/cm2 and 32.359 KV/cm in 5 V and 25.46 uC/cm2 and 41.94 KV/cm in 7 V, respectively. The crystalline structure and growth behavior of films have been studied by X-ray diffraction. The sol-gel + sputter composite double-layered PZT thin films lead to the highly (111) oriented PZT thin films. Moreover the applications of the composite double-layered PZT thin films, the diaphragm micro actuator for ultrasonic sensor is developed.